Figures
The architecture of cell differentiation in choanoflagellates and sponge choanocytes
Choanoflagellates are microscopic aquatic organisms that can alternate between single-celled and multicellular states, and sequencing of their genomes has revealed that choanoflagellates are the closest single-celled relatives of animals. Moreover, choanoflagellates are a form of 'collar cell–a cell type crowned by an array of finger-like microvilli and a single, whip-like flagellum. This cell type is also found throughout the animal kingdom; therefore, studying the structure of the choanoflagellate collar cell can shed light on how this cell type and animal multicellularity might have evolved. This study by Laundon et al. used electron microscopy to reconstruct in 3D the total subcellular composition of single-celled and multicellular choanoflagellates as well as the collar cells from a marine sponge, which represents an early-branching animal lineage. The image shows 3D serial ultrathin transmission electron microscopy reconstructions of single (upper row) and colonial (lower row) cells from the choanoflagellate Salpingoeca rosetta. Each row shows the cells with the plasma membrane rendered transparent (left), and after progressive removal of organelles (center, left).
Image Credit: pbio.3000226
Citation: (2019) PLoS Biology Issue Image | Vol. 17(4) May 2019. PLoS Biol 17(4): ev17.i04. https://doi.org/10.1371/image.pbio.v17.i04
Published: May 1, 2019
Copyright: © 2019 . This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Choanoflagellates are microscopic aquatic organisms that can alternate between single-celled and multicellular states, and sequencing of their genomes has revealed that choanoflagellates are the closest single-celled relatives of animals. Moreover, choanoflagellates are a form of 'collar cell–a cell type crowned by an array of finger-like microvilli and a single, whip-like flagellum. This cell type is also found throughout the animal kingdom; therefore, studying the structure of the choanoflagellate collar cell can shed light on how this cell type and animal multicellularity might have evolved. This study by Laundon et al. used electron microscopy to reconstruct in 3D the total subcellular composition of single-celled and multicellular choanoflagellates as well as the collar cells from a marine sponge, which represents an early-branching animal lineage. The image shows 3D serial ultrathin transmission electron microscopy reconstructions of single (upper row) and colonial (lower row) cells from the choanoflagellate Salpingoeca rosetta. Each row shows the cells with the plasma membrane rendered transparent (left), and after progressive removal of organelles (center, left).
Image Credit: pbio.3000226